
%0 Journal Article
%A Dyall, LK 
%T Pyrolysis of aryl azides. IV. Neighbouring group effects by <I>ortho</I> carbonyl groups
%J Australian Journal of Chemistry
%D 1977/12/01
%V 30
%N 12
%P 2669-2678
%K 
%R https://doi.org/10.1071/CH9772669
%U https://www.publish.csiro.au/paper/CH9772669 
%X The question of the mechanism by which ortho carbonyl groups enhance the rate of pyrolysis of aryl azides is examined. Rate measurements on sterically hindered 1-(2-azidophenyl)ethan-1-ones are consistent with the pericyclic mechanism proposed by Dyall and Kemp1 but not with the intramolecular 1,3-dipolar addition route put forward by Hall, Behr and Reed.2 A definitive test of mechanism is also provided by 1- azidoanthraquinone and 1-(2-azidophenyl)-2,2-dimethylpropan-1-for both of which the formation of a 1,3-dipolar adduct is precluded on steric grounds but the pericyclic process is not. At 393.2 K, these two azides pyrolyse 7385 and 61.7 times faster than phenyl azide, respectively. 
